Mixed salts of cesium and ammonium derivatives of 12-tungstophosphoric acid: Synthesis and structural characterization

Santos, Joicy Santamalvina dos; Dias, José A.; Dias, Sílvia C.L.; Garcia, Fillipe A.C.; Macedo, Julio L. de; Sousa, Flávia S.G.; Almeida, Liana S.

doi:10.1016/j.apcata.2010.12.034

Cited by 61 publications

(30 citation statements)

References 38 publications

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“…Obviously the manifold replacement of protons in one Keggin cage is favored over the formation of equally exchanged CsH 3 SiW 12 O 40 species. This is in agreement with recent literature reporting that precipitated HPW solids with a theoretical cation/heteropolyanion ratio of 1 at least form a mixture of the parent acid and a crystalline salt 70, 81.…”

Section: Glycerol To Acrolein Over Alkali Salts Of Heteropolyacidssupporting

confidence: 93%

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Recent developments in dehydration of glycerol toward acrolein over heteropolyacids

Martin

Armbruster

Atia

2011

Euro J Lipid Sci & Tech

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As biodiesel production from triglyceride transesterification increases, a surplus amount of by-product glycerol is produced. The glycerol production per year in Europe has tripled within the last 10 years to 800-900 kt per year. This motivates the development of new processes for the conversion of glycerol into valuable chemicals, e.g., the transformation into acrolein. It is an attractive intermediate for acrylates, methionine, glutaraldehyde, etc. In the recent years, some researchers studied the dehydration of glycerol to acrolein over acidic bulk and supported catalysts, in particular with heteropolyacids (HPAs) as active compounds. HPAs attracted the attention due to their high Brønsted acidity and well known structures, however, they have some disadvantages such as low surface area, low thermal stability, and rapid coking leading to deactivation. To overcome these drawbacks, HPAs are often supported on oxidic carriers showing high surface areas. In addition, redox active metals are incorporated into HPAs and oxygen-containing feed is used to suppress coke formation. This review presents a summary on recent research on HPA based catalysts in the gas phase dehydration of glycerol to acrolein.

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Section: Glycerol To Acrolein Over Alkali Salts Of Heteropolyacidssupporting

confidence: 93%

“…Thus, they can server either as homogeneous or heterogeneous catalysts. By proper replacement of metal species with redox metals, HPAs can be transformed into bifunctional catalysts also suited, e.g., for oxidation reactions 70–73. In many cases they can be recovered after reaction from liquid phase and reused 74.…”

Section: Heteropolyacidsmentioning

confidence: 99%

Recent developments in dehydration of glycerol toward acrolein over heteropolyacids

Martin

Armbruster

Atia

2011

Euro J Lipid Sci & Tech

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“…All the catalysts exhibited bands in the region of ñ = 1100-550 cm À1 called the fingerprint region of HPAs. [45] The band at ñ = 1080 cm À1 can be ascribed to the stretching vibration band of PÀO of the central PO 4 unit. The other bands at ñ = 983, 888, and 813 cm À1 are related to the asymmetric stretching of W=O t , (O t = terminal oxygen) asymmetric stretching of the corner oxygen in WÀO c ÀW (O c = corner-sharing bridging oxygen), and asymmetric stretching of tungsten with the edge oxygen in WÀO e ÀW (O e = edge-sharing bridging oxygen atom), respectively.…”

Section: Resultsmentioning

confidence: 99%

Samarium‐exchanged Heteropoly Tungstate: An Efficient Solid Acid Catalyst for the Synthesis of Glycerol Carbonate from Glycerol and Benzylation of Anisole

et al. 2012

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Samarium‐exchanged heteropoly tungstate (SmxTPA) is an efficient catalyst for the synthesis of glycerol carbonate from glycerol and urea. The catalysts with varying Sm content were prepared and characterized by FT‐IR spectroscopy, XRD, laser Raman spectroscopy, temperature‐programmed desorption of ammonia, and X‐ray photo electron spectroscopy. The activity of the catalysts is related to the Lewis and Brønsted acidity, which depends on the Sm content in the catalysts. Partially exchanged SmxTPA catalyst showed high activity, owing to a higher number of Lewis acidic sites. The catalyst exhibited consistent activity and selectivity during recycling. A plausible reaction mechanism is presented. The catalyst also exhibited high activity in the acid‐catalyzed benzylation of anisole.

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“…In comparison to the average size of triglyceride molecule 5.8 nm , the ferric-manganese doped tungstated molybdena catalyst has a big average pore size 84 nm , the reactants species would be certainly pass through the pores of FMWMo and consequently being more closely to the active sites, thus the best is performance of FMWMo catalyst. A Shimadzu X-ray fluorescence XRF with a Rayny EDX-720 spectrometer was used to find out the fraction of species existing in the catalyst 27,28 . The amount of Fe-Mndoped tungstated molybdena elements were found to be: iron Fe -1.542 manganese Mn -0.521 , tungsten W -20.437 , molybdenum Mo -77.5 .…”

Section: Biodiesel Determination Through Gc Analysismentioning

confidence: 99%

Biodiesel Synthesis Catalyzed by Transition Metal Oxides: Ferric-Manganese Doped Tungstated/Molybdena Nanoparticle Catalyst

2015

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Mixed salts of cesium and ammonium derivatives of 12-tungstophosphoric acid: Synthesis and structural characterization

Cited by 61 publications

References 38 publications

Recent developments in dehydration of glycerol toward acrolein over heteropolyacids

Recent developments in dehydration of glycerol toward acrolein over heteropolyacids

Samarium‐exchanged Heteropoly Tungstate: An Efficient Solid Acid Catalyst for the Synthesis of Glycerol Carbonate from Glycerol and Benzylation of Anisole

Biodiesel Synthesis Catalyzed by Transition Metal Oxides: Ferric-Manganese Doped Tungstated/Molybdena Nanoparticle Catalyst

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